The present invention is related to a hand tool, and more particularly to a ratchet wrench including a rotary switch for controlling two dogs to engage with the ratchet wheel.
A conventional ratchet wrench includes a ratchet wheel and a dog member engaged with the ratchet wheel for one-way rotating the ratchet wheel. Some of the ratchet wrenches are equipped with direction switches for changing the position of the dog member. Therefore, the dog member can engage with left side or right side of the ratchet wheel to control the rotational direction of the ratchet wheel. In a ratchet wrench free from the direction switch, the dog member is kept in a fixed position where the dog member is engaged with the ratchet wheel. A user must operate the wrench from front side or back side to change the rotational direction of the ratchet wheel.
U.S. Pat. No. 6,164,167 xe2x80x9cratchet wrench having gear driven pawlxe2x80x9d discloses a ratchet wrench having a direction toggle switch. A first, a second and a third recesses 121, 122, 123 are disposed in the head 11 of the wrench 10 and communicate with each other. A ratchet wheel 20, a toothed pawl 30 and a shifting block 41 are respectively received in said three recesses 121, 122, 123. Resilient members 51, 52 resiliently abut against the shifting block 41. The direction toggle switch 42 is connected with the shifting block 41. When turning the switch 42, the shifting block 41 is rotated to drive and move the toothed pawl 30 so as to change the engagement position of the toothed pawl and the ratchet wheel. Accordingly, the rotational direction of the ratchet wheel of the wrench can be controlled.
In the above conventional ratchet wrench having direction switch, only one pawl is disposed for engaging with the ratchet wheel.
Moreover, in the above ratchet wrench, the head 11 is formed with three recesses 121, 122, 123 for respectively accommodating therein the ratchet wheel 20, toothed pawl 30 and shifting block 41. As a result, the volume of the head 11 is enlarged and it is inconvenient to use such ratchet wrench. Furthermore, the manufacturing procedure is complicated. In addition, the top face of the head is hollow and covered by a cover board 70. This reduces the structural strength of the head.
It is therefore a primary object of the present invention to provide a ratchet wrench including a rotary switch for controlling two dogs to engage with the ratchet wheel and change the rotational direction of the ratchet wheel.
It is a further object of the present invention to provide the above ratchet wrench in which the head section of the handle of the ratchet wrench has minified volume.
It is still a further object of the present invention to provide the above ratchet wrench in which the structural strength of the head section is enhanced.
The present invention can be best understood through the following description and accompanying drawings wherein: